Treatment measures for the creep-slip phase of landslides induced by twin tunnels

Tunnel excavation in geologically challenging areas can lead to slope instability and consequent landslides, which pose a serious threat to the integrity of the tunnel lining. To address this issue, a study was conducted to investigate the stability of the tunnel-landslide system using the finite-difference method (FDM) based on the Hanshankou tunnel of the Shaoguan-Xinfeng expressway in Guangdong province, China. A plane-strain model was used to examine the effect of various treatment measures on the system, and the strength reduction (incremental) method was employed to determine the range of initial slope safety factors applicable to different treatment measures, with the maximum shear strain increment serving as the criterion. The 'anti-slip pile + anchor frame beam' reinforcement system was found to be the most effective solution, reducing daily deformation by 60.1% after implementation. The results indicated that the pile-anchor reinforcement system can significantly mitigate landslide creep, and the corresponding treatment measures can be categorised based on the critical slope safety factor under different conditions.